IN the wake of the tragic shooting deaths at Sandy Hook Elementary School in Newtown, Conn., last month, the National Rifle Association proposed that the best way to protect schoolchildren was to place a guard — a “good guy with a gun” — in every school, part of a so-called National School Shield Emergency Response Program.

Indeed, the N.R.A.’s solution to the expansion of gun violence in America has been generally to advocate for the more widespread deployment and carrying of guns.

I recently visited some Latin American countries that mesh with the N.R.A.’s vision of the promised land, where guards with guns grace every office lobby, storefront, A.T.M., restaurant and gas station. It has not made those countries safer or saner.

Despite the ubiquitous presence of “good guys” with guns, countries like Guatemala, Honduras, El Salvador, Colombia and Venezuela have some of the highest homicide rates in the world.

“A society that is relying on guys with guns to stop violence is a sign of a society where institutions have broken down,” said Rebecca Peters, former director of the International Action Network on Small Arms. “It’s shocking to hear anyone in the United States considering a solution that would make it seem more like Colombia.”

As guns proliferate, legally and illegally, innocent people often seem more terrorized than protected.

In Guatemala, riding a public bus is a risky business. More than 500 bus drivers have been killed in robberies since 2007, leading InSight Crime, which tracks organized crime in the Americas, to call it “the most dangerous profession on the planet.” And when bullets start flying, everyone is vulnerable: in 2010 the onboard tally included 155 drivers, 54 bus assistants, 71 passengers and 14 presumed criminals. Some were killed by the robbers’ bullets and some by gun-carrying passengers.

Scientific studies have consistently found that places with more guns have more violent deaths, both homicides and suicides. Women and children are more likely to die if there’s a gun in the house. The more guns in an area, the higher the local suicide rates. “Generally, if you live in a civilized society, more guns mean more death,” said David Hemenway, director of the Harvard Injury Control Research Center. “There is no evidence that having more guns reduces crime. None at all.”

After a gruesome mass murder in 1996 provoked public outrage, Australia enacted stricter gun laws, including a 28-day waiting period before purchase and a ban on semiautomatic weapons. Before then, Australia had averaged one mass shooting a year. Since, rates of both homicide and suicide have dropped 50 percent, and there have been no mass killings, said Ms. Peters, who lobbied for the legislation.

Distinctive factors contribute to the high rates of violent crime in Latin America. Many countries in the region had recent civil wars, resulting in a large number of weapons in circulation. Drug- and gang-related violence is widespread. “It’s dangerous to make too tight a link between the availability of weapons and homicide rates,” said Jeremy McDermott, a co-director of InSight Crime who is based in Medellín, Colombia. “There are lots of other variables.”

Still, he said that the recent sharp increase in homicides in Venezuela could be in part explained by the abundance of arms there. Although the government last spring imposed a one-year ban on importing weapons, there had previously been a plentiful influx from Russia. There is a Kalashnikov plant in the country.

In 2011, according to the United Nations Office on Drugs and Crime, Honduras led the world in homicides, with 91.6 per 100,000 people. But rates were also alarmingly high in El Salvador (69.1), Jamaica (40.9), Colombia (31.4) and Guatemala (38.5). Venezuela’s was 45.1 in 2010 but is expected to be close to to 80 this year. The United States’ rate is about 5.

THOUGH many of these countries have restrictions on gun ownership, enforcement is lax. According to research by Flacso, the Guatemalan Social Science Academy, illegal guns far outnumber legal weapons in Central America.

All that has spawned a thriving security industry — the good guys with guns that grace every street corner — though experts say it is often unclear if their presence is making crime better or worse. In many countries, the armed guards have only six weeks of training.

Guatemala, with approximately 20,000 police officers, has 41,000 registered private security guards and an estimated 80,000 who are working without authorization. “To put people with guns who are not accountable or trained in places where there are lots of innocent people is just dangerous,” Ms. Peters said, noting that lethal force is used to deter minor crimes like shoplifting.

Indeed, even as some Americans propose expanding our gun culture into elementary schools, some Latin American cities are trying to rein in theirs. Bogotá’s new mayor, Gustavo Petro, has forbidden residents to carry weapons on streets, in cars or in any public space since last February, and the murder rate has dropped 50 percent to a 27-year low. He said, “Guns are not a defense, they are a risk.”

William Godnick, coordinator of the Public Security Program at the United Nations Regional Center for Peace, Disarmament and Development in Latin America and the Caribbean, said that United Nations studies in Central America showed that people who used a gun to defend against an armed assault were far more likely to be injured or killed than if they had no weapon.

Post-Sandy Hook, gun groups in the United States are now offering teachers firearms training. But do I really want my kid’s teachers packing a weapon?

“If you’re living in a ‘Mad Max’ world, where criminals have free rein and there’s no government to stop them, then I’d want to be armed,” said Dr. Hemenway of Harvard. “But we’re not in that circumstance. We’re a developed, stable country.”

Correction: January 5, 2013

An earlier version of this article incorrectly referred to the Guatemalan Social Science Academy as Flasco. The correct acronym is Flacso.

Elisabeth Rosenthal is a physician and a science reporter for The New York Times.

A version of this news analysis appears in print on January 6, 2013, on page SR5 of the New York edition with the headline: More Guns = More Killing. Order Reprints|Today's Paper|Subscribe